Biocidal preparation

ABSTRACT

A biocidal preparation comprises a biocidally effective amount of a mixture of a compound of the general formula: WHEREIN R1 is alkyl with eight to 18 carbon atoms or benzyl which is chlorinated or brominated in 2- and/or 4-position and of a compound of the general formula: WHEREIN R2 is alkyl with seven to 17 carbon atoms. The weight ratio of the compounds I and II in the mixture is about 2 : 1 to 1 : 5.

United States Patent Hofmann et al.

[ 51 Aug. 22, 1972 [541 BIOCIDAL PREPARATION [221 Filed: Feb. 10,1970

21 Appl.No.: 10,280

[30] Foreign Application Priority Data Feb. 18, 1969 Germany ..P 19 08 078.5

[52] US. Cl ..424/263, 424/319 [51] Int. Cl. ..A0ln 9/02, A0ln 9/22 [58] Field of Search ..424/263, 319; 260/296 R [56] References Cited UNITED STATES PATENTS 2,080,517 5/1937 Tisza ..260/296 2,461,119 2/ 1949 Lott et al. ..260/296 X 3,225,074 12/ 1965 Cowen e? a1 ..424/319 X 3,328,307 6/1967 Schmitz ..424/316 X FOREIGN PATENTS OR APPLICATIONS 1,062,392 7/1959 Germany Primary Examiner-Albert T. Meyers Assistant Examiner-Doris]. Funderburk AttorneyMcGlew and Toren ABSTRACT A biocidal preparation comprises a biocidally effective amount of a mixture of a compound of the general formula:

11 N jqqnn wherein R is alkyl with eight to 18 carbon atoms or benzyl which is chlorinated or brominated in 2- and/or 4-position and of a compound of the general formula:

4 Claims, No Drawings HA. m.

BIOCIDAL PREPARATION CROSS REFERENCE TO PRIOR DISCLOSURE This invention has been disclosed in Disclosure Document 000009 deposited on Apr. 23, 1969.

FIELD OF THE INVENTION The invention relates to biocidal preparations.

BACKGROUND INFORMATION AND PRIOR ART In copending application Ser. No. 10,282 filed Feb. 10, 1970, N-substituted diaminopyridines of the formuhave been disclosed wherein R is alkyl with eight to 18 carbon atoms or stands for benzyl which is chlorinated or brominated in 2- and/or 4-position. The copending application demonstrates that such compounds have valuable biocidal characteristics. The compounds may be dissolved in organic solvents or may be dispersed iii strongly acidic aqueous media. However, as set forth in the copending application the compounds are poorly soluble in water. For this reason it is not possible to prepare from them clear aqueous solutions of high concentrations with an effective content of the compounds while maintaining an at least approximate physiological pH-value. For many purposes, however, clear disinfecting agent-containing preparations are desirable. This is particularly so if the disinfecting preparation is to be dispensed by means of automatic dosage devices and, generally, if mechanical or automatic dosage means are employed for diluting a concentrated master solution. Automatic dosage devices are generally employed at consumer stations where relatively large amounts of disinfecting preparations are dispensed. It will be appreciated that dispersions cannot effectively be dispensed by automatic dosage devices since the particles floating in the dispersion have the tendency to interfere with the sensitive dosage mechanism.

It has previously been proposed to improve the solubility of poorly soluble compounds of the general nature with which this invention is concerned by admixing the water with non-ionogenic, anionic and cationic tensides. The presence of these surface active agents frequently permits the preparation of relatively clear aqueous solutions of the compounds. However, a serious disadvantage of such a procedure is that the biocidal activity of the compounds is drastically reduced.

SUMMARY OF THE INVENTION It is a primary object of this invention to overcome the disadvantages of the prior art and to provide clear aqueous biocidal preparations of the N-substituted diaminopyridines referred to without having to resort to the use of tensides which reduce the biocidal effect.

Another object of the invention is to provide a biocidal preparation of the indicated kind which exerts superior biocidal characteristics.

biocidal preparation of the indicated kind in the form of a clear aqueous solution which can be readily dispensed by automatic dosage devices and which has a biocidal activity which is the same as or even superior to that of the prior art aqueous dispersions.

Briefly, and in accordance with the invention it has surprisingly been ascertained that biocidal preparations of increased biocidal effect and excellent water solubility can be prepared by admixing the compounds of formula I with certain preselected surface active betaines which in themselves have a rather low bacteriological activity.

The surface active betaines to be admixed with the compounds of formula I correspond to the general formula:

wherein R is alkyl with seven to 17 carbon atoms. The compounds of formula I should be admixed with the betaine compounds of formula II in a weight ratio of about2: l to l :5.

Accordingly the inventive biocidal preparation comprises a biocidally effective content of a mixture of compounds of the general formula:

wherein R is alkyl with eight to 18 carbon atoms or benzyl which is chlorinated or brominated in 2- and/or 4-position and compounds of the formula:

wherein R is alkyl with seven to 17 carbon atoms, the compounds of formula I and formula I] being present in the weight ratio of about 2 l to 1 5.

It will be understood that the compounds of formula I themselves may be mixtures or compounds with different chain lengths of the alkyl group. Such compound mixtures with different alkyl chain lengths are thus, for example, obtained by reacting 2,6-diaminopyridine with an alkylhalide or alkylsulphate derived from natu ral fats or products of the oxosynthesis. This has been elucidated in detail in the copending application referred to. The same applies to the compounds of formula II and the R group contained therein.

The fact that the biocidal activity of the compounds of formula I is increased by their admixture with compounds of formula II is certainly unexpected and surprising. This is so because surface active compounds which are chemically related with compounds of formula I, such as quaternary ammonium compounds and surface active amino acids which have a relatively pronounced bacteriological activity, are in respect to this bacteriological activity negatively affected by the addition of compounds of formula II. Thus, for example, if surface active amines are admixed with compounds of formula I], the bactericidal activity of the mixture is considerably less than that of the surface active amine alone. Experiments have indicated that the loss in bactericidal activity is still more pronounced if compounds of formula II are admixed with bactericides of a chemical structure somewhat further removed from the structure of formula I compounds, to wit, for example, halogen-alkylphenols or halogen-arylphenols or organo-tin compounds.

It will be appreciated that a decrease in the bactericidal activity caused by the solubilizing agents is most disadvantageous from a practical point of view since, generally, during actual use, protein and lipoid substances are frequently present in the form of contaminations which in any event cause a further considerable decrease in the biocidal activity of the preparation. It has been ascertained that the inventive preparations, containing compounds of both formula I and formula II are superior to prior art preparations since the loss in biocidal activity caused by such protein and/or lipoid contaminations is significantly less than that incurred by the prior art preparations.

The compounds of formula I may be prepared in the manner disclosed in the copending application. Generally, it may be stated that 2,6-diaminopyridine may be reacted with alkylhalide or alkylsulphate or with correspondingly chlorinated or brominated benzylhalide, preferably in the presence of an acid acceptor.

The compounds of formula ll may be prepared corresponding to the teachings of USA Pat. No. 3,225,074.

The preparation of the inventive synergistic mixture is effected in simple manner by dissolving the compounds of formula I in aqueous solutions of the compounds of formula II while adding acids, such as HCl, H 80 H PO CH COOH, CH CHOHCOOH and the like so as to obtain a pH-value of 7 or smaller. The mixing ratio between the formulal and formula II compounds may vary within wide limits but is advantageously within the range of 2 l to 1 5. The inventive mixtures are then obtained in the form of clear weakly colored aqueous solutions whose odor is primarily determined by the acid used, since the odor of the compounds of formula I and II proper is hardly noticeable.

The inventive preparations may thus be in the form of aqueous solutions which, however, may be admixed with additional components such as inorganic compounds, dyestuffs, scenting agents, thickeners and the like. However, it is also possible to supply the inventive preparations in the form of pastes, slurries or solids and to convert the preparations into aqueous solutions only just prior to or during use.

The superiority of the inventive mixtures in respect to their bactericidal activity is demonstrated in the following Tables.

BACI'ERIOLOGICAL RESULTS 1. Suspension test with 2-octylamino-6-amino-pyridine a. A 1 percent aqueous solution of 2-octylamino-6- amino-pyridine was prepared by adding 0.8 percent of a compound of the formula:

omooo III pH-value of the 1 percent solution was 4.3.

+ bacteria growth no bacteria growth action time in minutes concentration in 1 Test species Staphylococcus Aureus Pseudomonas Aeruginosa Proteus Vulgaris 0.1

| l l l i i i l l Escherichia Coli b. A 1 percent aqueous dispersion of 2-octylamino-6- amino-pyridine was prepared without addition of the formula III compound. However, acetic acid was added to the dispersion in an amount sufficient to establish a 4.3 pH-value. The results of the tests were as follows:

action time in minutes Test species concentration in% l 2 5 I0 20 30 Staphylo- 0.1 coccus Aureus 0.05

Pseudcmonas 0.1 Aeruginosa Proteus 0.1 Vulgaris Escherichia O.l Coli A comparison of the test results 1 a) and l b) clearly indicates that the inventive mixture 1 a) has surprisingly a much better bactericidal activity than the dispersion of 1 b).

2. Testing of the Protein Error of 2-octylamino-6- amino-pyridine As is known in this art, the term protein error indicates the loss of biocidal activity caused by the presence of protein. In order to test this protein error, an aqueous solution corresponding to 1 a) above was used whose different dilution stages were admixed with percent of serum from cows or oxen. As is indicated in the following Table, the bactericidal activity is hardly influenced by the addition of the serum:

Test species concentration action time in minutes 3. Bacteriological Investigations with Comparison Substances a). The bacteriological activity of C H NHCH CH -NH--CH --CH -NH-CH COOH without the addition of a fonnula 11 compound:

action time in minutes Test species concentration in l 2 5 10 20 Staphlo- 0.1 coccus Aureus 0.05

Pscudomonas 0.l Acruginosa Proteus 0.l Vulgaris Escherichia 0.] Coli b. The bacteriological activity of C H NHCH dition of a formula II compound (mixing ratio on molar basis corresponding to 1 0.005 Pseudomonas 0.1 Aeruginosa 0.0l Proteus 0.1 Vulgaris 0.01 Escherichia 0.1 Coli C. The bacteriological activity of HaC C 8 without the addition of the formula 11 compound.

A 10 percent solution of the compound in 1,2- propyleneglycol was produced and this solution was then diluted with water to the corresponding concentration:

Test species concentration action time in minutes in l 2 5 10 20 30 Staphylo- 0.l coccus Aureus 0.05 0.01 -'l- Pseudomonas 0.1 Aeruginosa 0.05 0.01 Proteus 0.1 Vulgaris Escherichia 0.1 Coli d. The bacteriological activity with the addition of a formula 1] compound.

A 10 percent solution of the chloroxylenol in a mixture consisting of 1,2-propyleneglycol and an amount of formula II compound was prepared. Said amount was sufficient so that upon dilution with water to a concentration of the formulal compound corresponding to 0.1 percent, a clear aqueous solution was obtained. This aqueous solution was found to be completely ineffective in respect to all 4 test species after a testing period of 30 minutes.

What is claimed is:

l. A bactericidal mixture comprising a compound of the formula:

Hm mm wherein R is selected from the group consisting of alkyl of eight to 18 carbon atoms, 2-chlorobenzyl, 4- chlorobenzyl, 2,4-dichlorobenzyl, 2-bromobenzyl, 4- bromobenzyl and 2,4-dibromobenzyl and a compound of the formula 5 wherein R is alkyl of seven to 17 carbon atoms, the weight ratio of said formula I and formula II com pounds being between about 2 l and l 5.

2. A substantially clear aqueous bactericidal preparation having a Ph valve of at the most 7 and comprising:

a. a compound of the formula:

wherein R is selected from the group consisting of alkyl of 8m 18 carbon atoms, 2-ch1orobenzyl, 4- chlorobenzyl, 2,4-dichlorobenzyl, 2-bromobenzyl, 4- bromobenzyl and 2,4-dibromobenzyl,

b a compound of the formula:

wherein R is selected from the group consisting of alkyl of 8 to 18 carbon atoms, 2-chlorobenzyl, 4- chlorobenzyl, 2,4-dichlorobenzyl, 2-bromobenzyl, 4-

bromobenzyl and 2,4-dibromo-benzyl, and further comprising an amount of a compound of formula:

0 CH3 R -ilNH(OH2)a- CH2COO wherein R is alkyl of seven to 17 carbon atoms, said amount of formula 11 compound being sufficient so as to completely dissolve said formula I compound in the water. 

2. A substantially clear aqueous bactericidal preparation having a pH valve of at the most 7 and comprising: a. a compound of the formula: wherein R1 is selected from the group consisting of alkyl of 8 to 18 carbon atoms, 2-chlorobenzyl, 4-chlorobenzyl, 2,4-dichlorobenzyl, 2-bromobenzyl, 4-bromobenzyl and 2,4-dibromobenzyl, b. a compound of the formula: wherein R2 is alkyl of seven to 17 carbon atoms and c) water, said formula I and formula II compounds being present in said preparation in a weight ratio of about 2 : 1 and 1 :
 5. 3. A preparation as claimed in claim 2, wherein said formula I compound is present in said preparation in an amount of about between 0.005 to 0.1 percent by weight.
 4. An aqueous bactericidal clear solution having a pH value of at the most 7 and comprising water, a compound of the formula: wherein R1 is selected from the group consisting of alkyl of 8 to 18 carbon atoms, 2-chlorobenzyl, 4-chlorobenzyl, 2,4-dichlorobenzyl, 2-bromobenzyl, 4-bromobenzyl and 2,4-dibromo-benzyl, and further comprising an amount of a compound of formula: wherein R2 is alkyl of seven to 17 carbon atoms, said amount of formula II compound being sufficient so as to completely dissolve said formula I compound in the water. 